function Bomb(){
    var set;
    this.start = function(){
        set = setTimeout(function(){
            console.log("爆炸");
        },3000)
    }
    this.clear = function(){
        clearTimeout(set);
        console.log("取消爆炸");
    }
}
var b1 = new Bomb();
var b2 = new Bomb();
b1.start();
b2.start();
var set1 = setTimeout(function(){
    b2.clear();
},1000)